The Tesi 3D E Looks Bizarre, but How Does That Hub Centre Steering Technology Actually Work? Here’S a Layman’S Guide
Total Page:16
File Type:pdf, Size:1020Kb
TRACK TEST >> BIMOTA TESI 3D E << The Tesi 3D E looks bizarre, but how does that hub centre steering technology actually work? Here’s a layman’s guide magine for a moment, you are lying in steered motorcycle in 1990. The later, Andrea has heaps more carbon fibre and a very handy hospital, all busted up from crashing your Acquaviva designed, iteration of this ground STM slipper clutch. bike on the racetrack. Leathers ripped, breaking bike, the 3D, looks quite similar to its The 3D Tesi’s Desmo donk is sandwiched ride trashed and your new Arai now only predecessor the 2D. However, Andrea started between a pair of beautifully machined good enough for the bin. Most normal with a relatively empty CAD computer screen aluminium billets serving as the main chassis people would be resting up, feeling sorry to produce a bike that corrected the 2D’s to which the front and rear swingarms are Ifor themselves. Not Massimo Tamburini. drawbacks of limited steering lock – improved mounted, while the steering head is attached In September, 1972 the now famous from 18° to 23° – a repositioned front shock to to a tubular-steel subframe coming off the designer crashed his Honda 750 Four at the clear the rider’s knees, a narrower build and a front of the billet chassis. Thanks to hub Misano racetrack in Italy – the stack left him simpler steering system to improve feel. centre design fundamentals, the 3D Tesi’s with three broken ribs. While recovering, The new-for-2012 Tesi 3D E is an evolution steering head does not see the mega load path TEST MARK MCVEIGH Signore Tamburini constructed a tubular of the 3D which includes a further revised front inherent on a traditional forked machine and PHOTOGRAPHY 404SHOTS steel frame to handle the power then being shock position. The 3D pull-rod mechanism is ultra lightweight as a result. The rear end FORK produced by the Japanese bikes. It was called hydraulic suspension which was located low is exquisitely detailed carbon-fibre complete the HB1 and that’s when Bimota was born. beside the engine has been replaced on this with its tidy solo seat, and the exhaust, Born from a young university graduate’s Evo version with a more traditional spring over headlight and dash come from the Delirio. mind, it was engineer Pierluigi Marconi’s damper shock directly mounted on the front The 3D Tesi E uses Ducati’s 1079cc dual- university thesis (“tesi” in Italian) that directly swingarm translating into more responsive spark engine producing 100hp (75kW) with led to the first Bimota Tesi 1D hub centre damping of the front end. The Evo version also 100Nm of torque. The placid nature of this off1 ! 2 Main: There’s no doubt it’s a unique-looking bike 1. Front end trellis swingarm and steering linkage 2. Rear shock settings are easily adjusted amcn /52 53/amcn 1 older motor doesn’t really fit with the 3D Tesi’s excellent with no rear wheel lock ups, the compression and rebound adjustability, although HUB CENTRE 2 high-tech mega-detailed chassis, however it STM dry slipper clutch working very well. I found the clickers a little insensitive to change makes the bike very easy to ride and it gets along This Bimota has extra connotations compared to the latest European superbikes. SCIENCE quite nicely if you keep the motor on the boil. The best described as a 3D feast of motorcycle This bike is a lot of fun. While I was getting power delivery is reasonably linear and smooth engineering jewellery. Every time I looked at caned down Lakeside Raceway’s straight by the although a little soft, so you definitely have to this smorgasbord of aluminium, chromalloy more powerful machines sharing the track on Rake: 21° Rake: 26° keep the revs up to maintain a decent pace. and carbon fibre, I’d spot some new intricate this rideday, the Tesi’s strengths – stability, agility A set of open pipes and some engine detail. The bike is one of only a handful in the and powerful, progressive brakes – meant I could re-mapping would certainly add to the ponies country and the others are in living rooms make up heaps of time, especially through the and sharpen up the power delivery. The motor like art pieces. The fact I was allowed to fang high-speed turns, chicanes and by trail braking 3 is pretty quiet, too, and by the day’s end I was this $50,000-plus bike around Queensland’s deep into the corners with the Brembo four-pot hanging for some Desmo tones. The electronics Lakeside racetrack is testament to the radial calipers on 320mm discs. are from Bimota and the motor redlines at motorcycling spirit of its owner, Mark Grant. Normally, motorcycle stability and agility are 9000rpm which I bounced off a few times before After testing all nine of the latest superbikes trade-offs, as front-end geometry with a larger, getting used to the relatively low rev ceiling. at AMCN’s AUSTest in June, I had a fresh feel for stable trail effectively reduces the bike’s roll The Ducati gearbox is reasonable, too – the latest motorcycling technology – and the 3D rate, making it harder to turn. The 3D Tesi is very Trail: 115mm Trail: 105mm but it’s a little notchy especially noticeable Tesi E was a big surprise. Mark is a solid 100kg stable yet also very manoeuvrable; not quite the on multiple downshifts where I can’t bang and it’s his weight that Bimota used to set the Panigale’s level of agility, but very respectable Hub centre steering has the potential to improve the down several gears at once, separating each bike up at the factory. I spent the morning tuning a 20-year-old design. The 3D is very narrow performance and safety of motorcycles because downshift instead to keep everything smooth. the spring preload and damping rates to suit and reasonably light, with a 167kg dry weight. it separates the steering, braking, and suspension Saying that, the well-spaced gears make my Leprechaun-esque 75kg. The Extreme Tech Lightweight Oz wheels and a centralised mass forces compared to the typical standard fork-equipped the best of the motor and engine braking is suspension has a good range of spring preload, combine to deliver excellent handling. motorcycle. The front suspension on a motorcycle equipped with a conventional fork is compressed under braking forces. This also has the effect of reducing the trail (see steering geometry) increasing the BIO The fact I was allowed to fang this $50,000-plus bike motorcycle’s roll rate or ability to turn, which reduces Mark McVeigh is a the motorcycle’s stability, compared to a hub centre freelance technical moto around a racetrack is a testament to its owner steering system. journalist, road-race Typical standard motorcycle forks also lack coach and development stiffness in comparison to hub centre steering, as they rider. Mark owns motoDNA, an Australian- act as a long lever to the headstock. This long lever based consultancy which provides high design also transfers large braking forces through performance road race coaching plus the frame headstock which subsequently is required design, prototyping and testing services to be very robust, adding to the bike’s weight and high to motorcycle manufacturers and race centre of mass. teams around the world. Hub centre steering is a triangulated design that, by nature, transfers loads directly to the chassis away 1. Dry slipper clutch works from the headstock, resulting in a lighter headstock a treat while the cover is design. This design also has the benefit of reduced carbon and billet art steering flex under heavy braking. 2. Brembo brakes are Also, hub centre steering systems typically use a powerful and progressive linkage which maintains steering geometry – namely 3. Dash from a Delirio trail – with front wheel travel, negating the adverse steering geometry change experienced when braking on a typical standard fork-equipped motorcycle. The king pin centreline defines the steering axis compared to a conventional forked motorcycle where the steering axis is generally through the headstock centreline. The 3D Tesi hub centre design has lots of positive handling benefits including low unsprung mass, high IN THE REAL WORLD rigidity, low steering inertia plus easy rake and trail If you’re riding a Bimota Tesi 3D, you’ll definitely adjustment. stand out from the crowd. The day after our track Hub centre steering motorcycles have been around test we rode to the popular motorcyclist’s haven of for a while now and have been relatively unsuccessful Canungra in the Gold Coast hinterland. commercially for a number of reasons – for instance, According to bike owner Mark Grant, the biggest some aesthetically unattractive designs have had a issue in the real world is the crowd control required negative effect on the motorcycling public’s perception. when you park up at the café with your mates. Technically, hub centre steering systems’ Achilles People swarm around the Tesi and just stare heel is the lack of front-end feel. This is mainly due in awe at this amazing machine with questions to the extra elements between the tyre contact patch aplenty; the most common query simply being, and the handlebars. If you think about a standard fork, “How does it work?” there is a very direct connection to the rider’s hands, Mark rode the bike as I had set it up at the which gives good tyre contact patch feedback. Hub track the previous day and reported a much more centre steering bikes however have extra parts, or compliant and smooth ride, deciding to leave the 3D elements, each with a certain amount of friction and Tesi as set up for a smaller 75kg pilot on the track, movement which reduces the sensitivity and feel to the maybe a reflection of the Queensland road surface.